This invention relates to an improved spiked-drum type fruit harvester.
The high cost of hand harvesting and difficulty of engaging suitable labor at critical times of harvest are serious problems for the fruit grower. The general purpose of this invention is to provide an improved harvesting device that will reduce labor cost and improve the economics and quality of the harvest. This is accomplished by oscillating the spikes or rods of the fruit harvester in a manner to achieve uniform acceleration and displacement to the fruiting canopy, thereby effecting efficient fruit removal. Although designed for brambles, it is envisioned that the improved shaker will have application to other small fruits such as blueberries and grapes.
Among the known types of mechanical harvesters for small fruit the spiked-drum shaker is preferred, because the spikes or rods gently enter the fruiting canopy as the harvester moves along the row. Oscillation of the spikes frees the ripe fruit from the entire canopy with minimal damage to the fruit or vine. The spiked-drum shaker is adaptable to continuous operation of the harvester along the row and to different configurations of the fruiting canopy.
Uniform acceleration of the spikes is a particularly desirable feature of the spiked-drum shaker. This results in uniform displacement of the fruiting canopy, and the force of oscillation may then be adjusted to the minimum amount required to remove the fruit with minimal damage to the vines. Uniformity of shaking action allows for better selectivity in removing mature fruit and leaving immature on the vine.
Heretofore it has not been possible to achieve uniform acceleration of the spikes in the same plane as the rotation of the drum as the harvester moves along the row.
Christie et al., U.S. Pat. No. 3,325,984 (June 20, 1967), describe a spiked-drum shaker oscillated by a directeccentric drive that gives uniform acceleration of the spike but oscillates in a motion perpendicular to the rotation of the drum.
Oscillation in the same plane as the rotation of the drum is provided by Perties with an eccentric cam, U.S. Pat. No. 3,255,578 (June 14, 1966), and by Weygandt et al. with weighted eccentrices, U.S. Pat. No. 3,245,211 (Apr. 12, 1966), but these methods produce substantial differences in acceleration at different points on the spike.